* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
  }
  
  body {
    margin: 0;
    padding: 0;
    height: 100vh;
    background-color: #f5f5f5;
    font-family: "source sans pro", sans-serif;
    display: flex;
    align-items: center;
    justify-content: center;
  }
  
  h1 {
    padding: 20px;
    text-align: center;
    font-size: 40px;
  }
  
  .paragraph {
    width: 70%;
    margin: 0 auto;
    padding: 20px;
    font-size: 20px;
    text-align: justify;
  }
  
  .toggle-btn {
    position: fixed;
    top: 40px;
    right: 40px;
    color: #f5f5f5;
    background-color: #000000;
    padding: 10px 20px;
    font-size: 16px;
    border: 1px solid #000000;
    border-radius: 5px;
    cursor: pointer;
  }
  
  .toggle-btn i {
    padding-left: 10px;
  }
  
  body.change-background {
    color: #f5f5f5;
    background-color: #000000;
  }
  